Parallel battery current equalizationTake a look at the above link. By "bad JuJu", when multiple batteries are wired in parallel and high current is drawn or high charging current is used, there can be issues with unequal current drain/charge to one or more of the batteries, leading to shorter battery life and less "run time" than might be expected. The web site above does a decent job of explaining how to connect multiple batteries in parallel while minimizing the unbalance charge/discharge.
I was 10 minutes later than the previous poster - same web site :B